Measurement and CAM convention
Measured Kerf Compensation
Turn a measured test coupon into a documented contour-offset decision. Compare simple centerline geometry with LightBurn’s software and Vernier-test conventions; none of the worked values is a material or machine preset.
Content reviewed 2026-11-02. Verify the applicability of each source before using a value in a quote.
Input to record
Uncompensated test geometry, target and measured dimensions, material/lot, thickness, head, nozzle, gas, focus, and software convention.
Output to carry forward
Measured kerf width or test-specific offset, recorded with contour direction, software field meaning, verification result, and review status.
Width and offset
For a symmetric kerf centered on an uncompensated path, the removed width is k and the contour correction is k / 2. An external part loses k across its overall width; an internal opening gains k. This geometric model assumes correct scale and an appropriate measurement method. Taper, roughness, corner behavior, motion error, and irregular beam shape can prevent a single value from correcting every feature.
Inspect the meaning of your CAM field before entering a number: it may request full kerf width, a radius/edge offset, or a test-specific value. The LightBurn Vernier file calculates the offset directly, so its D.E / 40 result must not be halved again. Its example 0.0575 mm is a documented demonstration, not a recommended compensation.
Measurement workflow
- Save an unchanged test drawing and record stock, process settings, orientation, and CAM revision. Set compensation to zero when the selected measurement method requires it.
- Cut a coupon with external and internal features. Measure repeat locations with a method suited to the drawing requirement; record raw results rather than only an average.
- Derive the width or test-specific offset. Record inside/outside direction and check the toolpath preview for overlap and nested contours.
- Cut a second coupon with the proposed correction. Release only after the actual dimensions meet the shop’s documented acceptance criteria.
- Re-test when material, thickness, nozzle, optics, focus, gas, speed, power, or orientation changes. Use the existing kerf calculator to review the quote input.
Kerf measurement record
Record your own setup and download a CSV. Fields stay in this page only, are not submitted, and clear on reload. A completed record is not approval of a machine setting.
Sources and scope
Content reviewed 2026-11-02. A documentation reference supports the stated method or data only; it does not approve settings on another machine.
- LightBurn 2.1: Kerf — What It Is and How to Compensate
Explains centerline material loss, closed-shape Line-mode offsets, automatic reversal for nested shapes, Preview inspection, the Vernier D.E/40 test formula, and direction-dependent beam effects. Software conventions apply to LightBurn, not every fiber CAM system.
Showing 5 of 5 rows
| Case | Inputs | Method | Output / decision | Source / section | Applicability | Confidence | Reviewed |
|---|---|---|---|---|---|---|---|
| External coupon; uncompensated centerline | Illustrative target 20.00 mm; measured 19.80 mm | Kerf = 20.00 − 19.80 = 0.20 mm | Centerline moves outward by kerf / 2 = 0.10 mm | Derived symmetric-kerf geometry; LightBurn guide explains centerline material loss | Illustrative arithmetic only; assumes centered symmetric kerf, no existing compensation or scale error | Geometry example; not a measured production value | 2026-11-02 |
| Internal hole; uncompensated centerline | Illustrative target 10.00 mm; measured 10.20 mm | Kerf = 10.20 − 10.00 = 0.20 mm | Centerline moves into the hole by kerf / 2 = 0.10 mm | Derived symmetric-kerf geometry; LightBurn guide explains oversize slots | Illustrative arithmetic only; straight edge/diameter measurement must match the intended feature | Geometry example; verify on a second coupon | 2026-11-02 |
| LightBurn Line-mode convention | Closed shapes on a layer; inspect inside and outside contours | Positive expands border; negative shrinks border | Nested shapes on the same layer invert offset direction automatically; inspect Preview | LightBurn 2.1: Applying a Kerf Offset | LightBurn only; CAM systems may request full kerf width or use different signs | Documented software convention; not universal CAM behavior | 2026-11-02 |
| LightBurn Vernier test-file convention | Guide example D = 2; E = 3, giving 2.3 | 2.3 / 40 = 0.0575 mm | Enter the result as that test’s Kerf Offset; do not divide by two again | LightBurn 2.1: Finding the Correct Kerf Offset Value | Only the linked LightBurn test geometry and instructions; not a general coupon formula | Published worked example; not your machine’s measured kerf | 2026-11-02 |
| Direction or setup changes | Repeat X/Y features; record material, thickness, speed, power, focus, gas, and nozzle | Compare repeated measured results before selecting compensation | Keep orientation-specific results; retest after changes rather than averaging unsupported values | LightBurn 2.1: Irregular Beam Shapes; guide introduction on material/settings dependency | Diagnostic check; acceptable variation comes from the drawing/shop requirement | Documented variability; shop validation required | 2026-11-02 |
Reference workflow
- Match the job, material, machine head, and quality requirement to a row.
- Confirm the source, review date, and confidence before copying the value into a quote worksheet.
- Use a measured result or current OEM record when the row is marked as required or unverified.